Lieutenant-Colonel Bitala Madjoulba, who commanded the country's Rapid Intervention Battalion (BIR), was found dead in his office on the night of May 3-4, 2020, hours after attending the inauguration of President Faure Gnassingbe, who had been re-elected for a fourth term.

Madjoulba's battalion was at the forefront of a brutal suppression of demonstrations which attracted huge crowds in 2017 and 2018.

The unexplained death of such a high-ranking figure posed a challenge to the authorities in Togo where the armed forces have been the cornerstone of power for 60 years.

Opposition figures have criticised the silence authorities have thus far maintained while also demanding an independent inquiry.

The investigators, overseen by Security Minister General Damehame Yark, only broke their silence on July 13 to say that Togo had asked France to provide "technical help".

Local media quoting the prosecutor, Essolissam Poyodi, reported that a bullet was extracted from Madjoulba's body during an autopsy.

In his first public statement on the case, the prosecutor on Friday announced that "after ballistic examinations conducted in Ghana", a murder weapon had been identified

A group of experts spent nine hours reconstructing the chronology of events, he said, adding that no details regarding the type of weapon could be shared.

"The ongoing investigation will lead to the identification of one or several authors and accomplices in this crime," said Poyodi.

Local media have suggested the crime was the result of divisions within the military, "a settling of scores".

The investigation "is a hot potato," said David Dosseh, spokesman for an umbrella group of citizens' groups called Togo Citizens' Front Upstanding, or FCTD in its French initials.

Locals in the late colonel's home village in Siou, more than 500 kilometres (300 miles) north of the capital Lome, have staged several protests demanding greater transparency over his death.